Cutting torch nozzle and method



Dec. 16, 1969 F. DOMBRUCH ETAL 3,484,044

CUTTING TORCH NOZZLE AND METHOD Originai Filed Aug. 17, 1964 UnitedStates Patent US. Cl. 239-8 8 Claims ABSTRACT OF THE DISCLOSURE Acutting torch nozzle includes a central stream of cutting oxygen, anintermediate annular stream of fuel gas surrounding the cutting oxygen,and an outer annular stream of additional oxygen surrounding the fuelgas. The fuel gas mixes externally with the oxygen supplied from boththe central cutting stream and the outer additional stream. The outerstream also acts as a shield for the fuel gas to assure its completecombustion and minimize mixture with the air which would result inundesired carbon deposits or soot.

CROSS-REFERENCE TO RELATED APPLICATION This application is acontinuation of copending application Ser. No. 389, 859, filed Aug. 17,1964, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a nozzle for ametal cutting torch, and more particularly to such a cutting torch whichexternally mixes oxygen with its fuel.

In cutting and flame torches it is often customary to use an oxygenstream and post-mixed preheating flames, that is flames formed by thecombustion fuel gas and oxidizing gas mixed externally of the nozzle, inorder to avoid the formation of an inflammable gas mixture with in thetorch, and hence undesirable reactions in the torch such as backfiring.Some torches do not add a special heating oxygen stream to the fuel butinstead construct the nozzle head in such a manner that the fuel obtainsthe oxygen necessary for or erly combustion, from the actual cutting orflame oxygen stream. This is achieved in a simple manner in that thefuel as well as the cutting or flame oxygen stream openings are situatedso close to each other that the flames are formed immediately at theedge area of the oxygen stream.

The use of this principle of outside mixture has very good results inworking with an oxygen stream having slight exhaust speed, as is oftenused in flame torches for instance, particularly in the use of acetyleneor gases burning slower than acetylene, such as coal gas, propane, orthe like. There are difliculties, however, in cases where a high heattolerance and heat concentration and where a sufiicient combustion ofthe gas is not too great a distance from the work piece, are requiredwith the oxygen streams having high velocity as is the case, forexample, in torch cutting.

An object of this invention is to provide a nozzle for effectivelymixing fuel with oxygen streams outside a metal cutting torch.

SUMMARY OF THE INVENTION In acordance with this invention a constantlysatisfactory flame formation is achieved, irrespective of the fuel used,in cutting torches by means of a nozzle having one or more furtheroxygen exhaust openings closely arranged to the fuel exhaust openingswith correspondingly the fuel exhaust openings surrounding the centralcutting oxygen passage. In other words the fuel is concentricallyarranged between two streams of oxygen. Thus correlation is broughtabout in that the areas of the emerging fuel gases which are divertedfrom the central cutting oxygen stream also come in contact with theadditional oxygen stream to thereby achieve by a double outer mixture asatisfactory intermixture fuel gas and oxygen.

Stated in another manner the intermediate fuel stream mixes with oxygenfrom the central cutting stream as well as with oxygen from the outerannular stream. The outer stream of oxygen has the added function ofshielding the fuel from the air which assures a complete combustion ormixing of the fuel while preventing the formation of carbon deposits orsoot. For example arrangements which contain outer streams of fuel gasor of premixed gases (such as disclosed in US. Patents 2,407,972 and2,243,184) permit a mixture of the air and fuel gas. Since aircontainsover nitrogen and other inert gases there is an incompletecombustion in that the fuel gas is not fully oxidized. This in turnresults in carbon formations or soot on the workpiece which increasesthe strength of the workpiece rendering it more difficult to cut or workwith at some subsequent time. Additionally the type of cut achieved withsuch prior devices would be wavy and of varying thickness or non-uniformdue to the instable fluttering of the pro-heat mixture. With theshielded fuel stream of this invention there is complete combustionwhich enables a smooth, sharp, uniform, narrow cut to be obtained fromthe more concentrated cutting stream.

In one form of this invention the nozzle top for the cutting torch isconstructed by providing the additional oxygen exhaust openingsconcentrically around the round fuel gas exhaust slot or the ring ofindividual openings for fuel gas exhaust, either in the form of anannular passage or a num er of individual passages of any diameterdesired. When the fuel gas exhaust is made up of a ring of individualopenings or passages, the additional oxygen exhaust openings may bearranged in the ring area of the fuel gas openings in an alternatingmanner. In other words all of the additional oxygen exhaust openings arenot radially aligned with the fuel openings. In all of thesearrangements of the additional oxygen exhaust openings and the fuel gasopening there results in an especially eflective manner a double outermixture, irrespective of the central cutting oxygen passageway.

This double outer mixture may also be accomplished by constructing thenozzle tip for the cutting torch with the additional oxygen exhaustopenings concentrically surrounding the round fuel gas exhaust slot orthe ring of individual openings for the fuel gas exhaust, either in theform of an annular opening or a number of individual openings of anycross section desired.

Other objects and many attendant advantages of this invention will bereadily appreciated as the same become better understood by reference tothe following detailed description when considered in connection withthe accompanying drawings.

BRIEF DESCRIPTION OF DRAWING FIGS. 1-3 are crosssectional views of threeembodiments of this invention; and

FIG. 4 is a side view partially broken away and in section of the nozzleshown in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION FIG. 4 shows the generalarrangement of a cutting torch head 10 incorporating one of the nozzles1 of this invention. As shown in FIG. 4 cutting oxygen is suppliedthrough conduit 7 into central bore 1 of torch head and nozzle 11.Conduit 8 conducts the gaseous fuel through a number of apertures orspaced coarcuate passageways 12 which are concentric with central oxygencutting passageway 1. Additional oxygen is supplied through conduit 9into spaced passages 23 in jacket 26 concentrically arranged aboutpassages 12.

FIG. 1 shows one form of a nozzle where there are arranged around thecentral cutting oxygen bore or passage 1, an annular or ringlike passageor slot 2 for fuel gas in place of individual passages. Surroundingpassage 2 is another annular channel 3 for supplying the additionalheating oxygen.

The nozzle tip represented in FIG. 2 is constructed in two parts. Theactual cutting nozzle 4, which contains the central cutting oxygen bore1, is provided with slots or grooves 12 on its outer surface. Heatingcap 5 is secured to and surrounds nozzle 4 to thus transform slots orgrooves 12 into closed canals or passages for the fuel gas. Cap 5 alsohas a plurality of grooves or slots 13 on its outer surface which, inturn become canals or passages for the additional oxygen when jacket 6is screwed on or otherwise secured on or otherwise secured to cap 5.

FIG. 3 is a cross-sectional view of the nozzle 11 shown in FIG. 4 andincludes a sleeve 26 surrounding cutting nozzle 4 which contains centraloxygen passage 1. Nozzle 4 is provided with spaced longitudinal grooves12 which form fuel passages when jacket 26 is secured to nozzle 4.Sleeve or jacket 26 has a series of spaced longitudinal passages 23which conduct the additional oxygen. In this arrangement the need for aspecial heating cap such as cap 5 of FIG. 2, is eliminated.

By means of the nozzles shown, there is achieved in an especiallyadvantageous manner a double outer mixture of the fuel gas. The purefuel gas, leaving slot or annular passage 2 or canals 12, obtains itsheating oxygen in the usual manner from the edge area of the centralcutting oxygen stream, which streams through bore 1. Additionally,however, for the obtainment of a sufficient mixture, there is mixed tothe fuel gas additional oxygen which passes through annular passageway3, or canals 13, or bores 23. This additional oxygen not only providesan added supply of oxygen to the fuel but also shields the fuel from thesurrounding air.

The invention can be effected in various ways and is not limited to theexamples shown. Thus, the arrangement and diameter size of the exhaustcanals or passages for the actual cutting oxygen, fuel gas, as well asadditional oxygen are entirely arbitrary and depend on the requirementsand circumstances of a particular case. For example, the exhaustopenings for the additional oxygen can be installed in the same exhaustring or annular member as the fuel gas, particularly in such a mannerthat the gas and oxygen exhaust openings are alternatively arranged. Forexample as shown in FIGS. 2-3 all of the additional oxygen passageways13 or 23 are not radially aligned with fuel passageways 12. In all casesit is also essential that the nozzle tipnext to the cutting oxygenexhaust-is at a suitable place, or in the corresponding area of thefurther oxygen exhaust openings, to enable a double outer mixture of thefuel gas.

Similarly, the principle of the double outer mixture can be used fortorches of other types and nature, eg for flame torches or the like.This concept can thus be used in cases where any other cross-sectionforms for the gas and oxygen exhaust are present, such as elongated exhaust slots for the oxygen with heating gas exhaust openings in the formof bores or slots mounted above and/ or below the oxygen exhaustopenings.

The nozzle of this invention which enables such double outer mixture isnot only of importance in the use of gases with more slight exhaustvelocity as acetylene; but

also in the use of acetylene, since despite its comparatively highoxidation velocity there results in the outer zone of the flame openingand incomplete oxidation which forms undesired carbon deposits or sooton the workpiece. This soot has a detrimentral affect on the strength ofthe workpiece. This carbon deposit is avoided, however, in the use of anouter oxygen sheet around the acetylene, and there occurs, furthermore,because of the additional oxygen an intensive burning and thus makes abetter utilization (i.e. complete combustion) of the acetylene. Thenozzle of this invention is, of course, not limited to a particular typeof fuel gas.

Finally, by means of correspondingly logical arrangement of the furtherfuel gas, and oxygen exhaust openings adjacent thereto, the double outermixture can be extended to a multiple outer mixture, as it is consideredfor example in preheating torches with large effective surfaces.

What is claimed is:

1. A nozzle for a torch operated by the external mixing of its gasescomprising a central cutting oxygen stream outlet, a plurality of gaspassageways concentrically arranged about said central outlet forconducting a corresponding number of unmixed gases from the torch. saidoutlet and said passageways being coterminous whereby internal mixing isavoided, said central outlet having a feed end and a discharge end,means connected to said feed end for feeding cutting oxygen gas throughsaid outlet, said plurality of passageways comprising a pair ofpassageways, one of said passageways being an intermediate passagewayconcentrically arranged between one of the said passageways and saidcentral outlet, the other of said passageways being an outer passageway,means connected to the feed end of said intermediate passageway forfeeding fuel gas therethrough, and means connected to the feed end ofsaid outer passageway for feeding additional oxygen therethrough.

2. A nozzle as set forth in claim 1 wherein said intermediate passagewayis a continuous annular passageway.

3. A nozzle as set forth in claim 1 wherein said outer additional oxygenpassageway is a continuous annular passageway.

4. A nozzle as set forth in claim 1 wherein said cutting oxygen outletis a bore in a central member, a plurality of longitudinal grooves beingin the external surface of said central member, a sleeve fitting oversaid central member to form a top wall for said grooves, and saidplurality of grooves being said intermediate passageway for said fuelgas.

5. A nozzle as set forth in claim 4 wherein a second plurality ofgrooves are in the external surface of said sleeve, an outer memberfitting over said sleeve to form a top wall for said second plurality ofgrooves, and said second plurality of grooves being said outerpassageway for additional oxygen.

6. A nozzle as set forth in claim 1 wherein said intermediate fuelpassageway is a set of spaced coarcuate passageways, said outeradditional oxygen passageway being a set of spaced coarcuatepassageways, and at least some of said additional oxygen passagewaysbeing radially non-aligned with corresponding fuel pasageways.

7. In a process for externally mixing gases from a torch nozzlecomprising supplying a cutting stream of oxygen through a central outletin the nozzle, supplying an intermediate annular stream of pure fuel gasthrough a passageway around said central outlet, supplying an outerannular stream of additional oxygen through a passageway around saidfuel gas passageway, mixing said fuel gas externally of said nozzle withoxygen from both said central stream and said outer stream, andshielding said fuel gas from the atmosphere by said outer stream ofadditional oxygen.

8. In a process as set forth in claim 7 wherein only unmixed gases areemitted from said nozzle.

(References on following page) 6 References Cited EVERETT W. KIRBY,Primary Examiner UNITED STATES PATENTS MICHAEL Y. MAR, AssistantExaminer 3,364,970 1/1968 Dombruch et a1 239422 2,243,184 5/1941 Aronsonet al. US. Cl. X.R. 2,657,650 11/1953 Chouinard et a1. 26623 X 5239-422, 424; 266-23; 431--1O FOREIGN PATENTS 494,218 10/1938 GreatBritain.

890,332 9/1953 Germany. 10

